Dear Susan,
I asked a similar question about postage stamp storage a bit ago and got very
helpful responses, including:

-  Many commercially available philatelic holders are acidic glassine or
unstable PVC, neither of which is good.  The company, TaylorMade (P.O. Box
406, Lima, PA 19037) has mylar holders available.  The company owner, Tuck
Taylor, is also a stamp collector.

-  University Products (800-628-1912) carries archival stamp mounts and
holders.  One respondent recommended the best being Showgard or Hawid mounts
with either black or clear backings which can be obtained at a good price from
Subway Stamps in New York.

-  Three reports on various commercial products (i.e. acid content of album
pages and other philatelic supplies) have been produced by the Arthur Salm
Foundation, 1029 N. Dearborn St., Chicago, IL  60610

-  Other potentially helpful sources of information include:  American
Philatelic Society; the Canadian Postal Museum which is part of the Canadian
Museum of Civilization in Hull, Ontario
([log in to unmask]); the National Postal Museum,
Smithsonian Institution, 2 Massechusetts Ave., NE, Washington, DC  20560.

- And last but not least, Paul Fox from the National Philatelic Center in
Melbourne, Australia sent me a very help booklet "Caring for Your Stamp
Collection."  I'd be happy to share that with you if you send me your snail
mail address.

Hope this helps.

Deborah Cooper
Museum Collections Coordinator
Oakland Museum of California